Fix drop command bug (#25)

Update coop command
Add /killall to CustomCommands

Source/GrasscutterTools/Resources/zh-cn/CustomCommands.txt

@@ -41,7 +41,7 @@
 私信
 /say <player> <message>
 进来吧你
-/coop <playerId> <target playerId>
+/coop @targetId
 自杀
 /killcharacter
 暗杀
@@ -49,4 +49,6 @@
 都有谁在？
 /list uid
 重载服务配置
-/reload
+/reload
+清场
+/killall